Materials Offer No New Information on Flight's Whereabouts

KUALA LUMPUR, Malaysia—After Malaysia Airlines Flight 370 veered off its course, civilian air-traffic controllers spent precious predawn hours in befuddled exchanges with counterparts in nearby countries in an effort to locate the jet, according to documents released by investigators Thursday.

A series of missteps began less than an hour after the plane disappeared around 1:20 a.m. on March 8.